{"id":10988,"date":"2021-06-04T13:20:26","date_gmt":"2021-06-04T11:20:26","guid":{"rendered":"https:\/\/itechmedicaldivision.com\/?p=10988"},"modified":"2022-01-13T12:00:52","modified_gmt":"2022-01-13T11:00:52","slug":"effects-of-ultrasound-therapy-on-biological-tissues","status":"publish","type":"post","link":"https:\/\/itechmedicaldivision.com\/en\/effects-of-ultrasound-therapy-on-biological-tissues\/","title":{"rendered":"Effects of ultrasound therapy on biological tissues"},"content":{"rendered":"\t\t
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Ultrasound is defined as an acoustic vibration with frequencies above those deemed audible by the human ear (i.e. greater than 20 kHz). It spreads in the form of mechanical compression-rarefaction waves with coming and going movement of the particles of the transmission medium (head), parallel to the direction of the propagation waves.<\/p>

The ultrasonic waves are artificially produced through the piezoelectric effect, exploiting either a quartz or a disc of ceramic material. Applying electric charges on the faces of a quartz plate, the crystal compresses, while inverting the direction results in an expansion. By subjecting the quartz to an alternating electric field, therefore, an alternation of compressions and expansions of the crystal is produced with the consequent series of vibrations used in therapy.<\/p>

The ultrasonic waves travel through the tissue transferring energy. The interaction of ultrasonic waves with biological tissues produces mechanical, thermal, chemical and cavitation effects.<\/p>

Mechanical effects<\/h2>

The mechanical action is due to the movement of the particles of the tissues crossed by the ultrasonic wave. The variations in pressure that are produced are able to move liquids, an increase in membrane permeability and disrupt tissues through the separation of collagen fibres.<\/p>

Thermal effects<\/h2>

The thermal effect depends on two main factors: the absorption characteristics of the biological medium and the energy reflection at an interface level between tissues with different acoustic impedance.<\/p>

The passage of ultrasonic waves through the “soft” tissues creates an increase in temperature due to absorption linked to viscosity, absorption due to thermal conductivity and chemical absorption.<\/p>

Chemical effects<\/h2>

The chemical action with alteration of the local pH and of the permeability of the cell membranes and with molecular changes is caused by the considerable acceleration forces at which the particles of the tissues are subjected to with the passage of the ultrasonic wave.<\/p>

This action, therefore, favours the penetration of active ingredients.<\/p>

Cavitation effects<\/h2>

Cavitation is the ability of the ultrasonic waves to generate small bubbles of dissolved gas within a fluid with subsequent increase in size and possible explosion of bubbles.<\/p>

In this way a gradual disintegration of fat cells is obtained resulting in the reduction in the volume of adipose tissue.<\/p>

Transmission through tissues<\/h2>

Ultrasonic waves travelling through tissue lose a certain portion of their energy. This process is known as attenuation<\/strong>.<\/p>

Attenuation in the tissue is produced by many mechanisms such as absorption, beam divergence and deflation.<\/p>

Absorption<\/strong> is the main cause of ultrasonic wave attenuation. The ultrasonic energy is absorbed by the tissue and converted into heat.<\/p>

For most tissues, attenuation increases with increasing frequency. Thus, a 1.0 MHz signal penetrates more deeply than a 3.0 MHz signal, due to the lower attenuation in the tissue.<\/p>

The divergence<\/strong> of the beam is the degree to which the beam disperses from the transducer. The divergence of the beam decreases as the frequency increases and, therefore, a higher frequency signal has a more focused beam.<\/p>

Deflation includes<\/strong> the process of reflection, refraction and dispersion.<\/p>

An ultrasound therapy device consists mainly of an alternating current generator (typically 1 MHz and\/or 3 MHz) that feeds an emitting head in which a transducer (piezoelectric disc or quartz plate) is inserted. This transducer converts electrical energy into mechanical energy (acoustic vibrations that are transmitted to the tissues).<\/p>

There are also ultrasound therapy devices that use very low frequencies (20-70 KHz) for aesthetic applications only.<\/p>

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Ultrasound is defined as an acoustic vibration with frequencies above those deemed audible by the human ear (i.e. greater than […]<\/p>\n","protected":false},"author":11,"featured_media":9083,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[69],"tags":[],"class_list":["post-10988","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-reserved-news","col-lg-4 col-md-6"],"acf":[],"_links":{"self":[{"href":"https:\/\/itechmedicaldivision.com\/en\/wp-json\/wp\/v2\/posts\/10988","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/itechmedicaldivision.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/itechmedicaldivision.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/itechmedicaldivision.com\/en\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/itechmedicaldivision.com\/en\/wp-json\/wp\/v2\/comments?post=10988"}],"version-history":[{"count":0,"href":"https:\/\/itechmedicaldivision.com\/en\/wp-json\/wp\/v2\/posts\/10988\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/itechmedicaldivision.com\/en\/wp-json\/wp\/v2\/media\/9083"}],"wp:attachment":[{"href":"https:\/\/itechmedicaldivision.com\/en\/wp-json\/wp\/v2\/media?parent=10988"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/itechmedicaldivision.com\/en\/wp-json\/wp\/v2\/categories?post=10988"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/itechmedicaldivision.com\/en\/wp-json\/wp\/v2\/tags?post=10988"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}